From 06e31f51024e58b50bc107495242e7104599b995 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 16 Aug 2017 12:39:15 -0400
Subject: [PATCH] Consequential to the 6502 change, severs the Atari 2600's
 cartridge container from its former attempt at runtime polymorphism, in
 favour of each cartridge's specific hardware being defined as a 'bus
 extender'.

---
 Machines/Atari2600/Atari2600.cpp              | 54 +++++++++----------
 ...ctivisionStack.hpp => ActivisionStack.hpp} | 19 ++++---
 .../{CartridgeAtari16k.hpp => Atari16k.hpp}   | 22 ++++----
 .../{CartridgeAtari32k.hpp => Atari32k.hpp}   | 18 +++----
 .../{CartridgeAtari8k.hpp => Atari8k.hpp}     | 22 +++-----
 ...CartridgeCBSRAMPlus.hpp => CBSRAMPlus.hpp} |  9 ++--
 Machines/Atari2600/Cartridges/Cartridge.hpp   | 29 +++++++---
 .../{CartridgeCommaVid.hpp => CommaVid.hpp}   |  7 +--
 .../{CartridgeMNetwork.hpp => MNetwork.hpp}   | 11 ++--
 .../{CartridgeMegaBoy.hpp => MegaBoy.hpp}     | 10 ++--
 ...CartridgeParkerBros.hpp => ParkerBros.hpp} | 10 ++--
 .../{CartridgePitfall2.hpp => Pitfall2.hpp}   | 19 ++++---
 ...rtridgeTigervision.hpp => Tigervision.hpp} | 12 ++---
 .../{CartridgeUnpaged.hpp => Unpaged.hpp}     |  7 ++-
 .../Clock Signal.xcodeproj/project.pbxproj    | 48 ++++++++---------
 15 files changed, 145 insertions(+), 152 deletions(-)
 rename Machines/Atari2600/Cartridges/{CartridgeActivisionStack.hpp => ActivisionStack.hpp} (73%)
 rename Machines/Atari2600/Cartridges/{CartridgeAtari16k.hpp => Atari16k.hpp} (66%)
 rename Machines/Atari2600/Cartridges/{CartridgeAtari32k.hpp => Atari32k.hpp} (66%)
 rename Machines/Atari2600/Cartridges/{CartridgeAtari8k.hpp => Atari8k.hpp} (65%)
 rename Machines/Atari2600/Cartridges/{CartridgeCBSRAMPlus.hpp => CBSRAMPlus.hpp} (75%)
 rename Machines/Atari2600/Cartridges/{CartridgeCommaVid.hpp => CommaVid.hpp} (78%)
 rename Machines/Atari2600/Cartridges/{CartridgeMNetwork.hpp => MNetwork.hpp} (86%)
 rename Machines/Atari2600/Cartridges/{CartridgeMegaBoy.hpp => MegaBoy.hpp} (78%)
 rename Machines/Atari2600/Cartridges/{CartridgeParkerBros.hpp => ParkerBros.hpp} (78%)
 rename Machines/Atari2600/Cartridges/{CartridgePitfall2.hpp => Pitfall2.hpp} (89%)
 rename Machines/Atari2600/Cartridges/{CartridgeTigervision.hpp => Tigervision.hpp} (71%)
 rename Machines/Atari2600/Cartridges/{CartridgeUnpaged.hpp => Unpaged.hpp} (74%)

diff --git a/Machines/Atari2600/Atari2600.cpp b/Machines/Atari2600/Atari2600.cpp
index 0d705ed45..c640dc91b 100644
--- a/Machines/Atari2600/Atari2600.cpp
+++ b/Machines/Atari2600/Atari2600.cpp
@@ -10,18 +10,18 @@
 #include <algorithm>
 #include <stdio.h>
 
-#include "Cartridges/CartridgeAtari8k.hpp"
-#include "Cartridges/CartridgeAtari16k.hpp"
-#include "Cartridges/CartridgeAtari32k.hpp"
-#include "Cartridges/CartridgeActivisionStack.hpp"
-#include "Cartridges/CartridgeCBSRAMPlus.hpp"
-#include "Cartridges/CartridgeCommaVid.hpp"
-#include "Cartridges/CartridgeMegaBoy.hpp"
-#include "Cartridges/CartridgeMNetwork.hpp"
-#include "Cartridges/CartridgeParkerBros.hpp"
-#include "Cartridges/CartridgePitfall2.hpp"
-#include "Cartridges/CartridgeTigervision.hpp"
-#include "Cartridges/CartridgeUnpaged.hpp"
+#include "Cartridges/Atari8k.hpp"
+#include "Cartridges/Atari16k.hpp"
+#include "Cartridges/Atari32k.hpp"
+#include "Cartridges/ActivisionStack.hpp"
+#include "Cartridges/CBSRAMPlus.hpp"
+#include "Cartridges/CommaVid.hpp"
+#include "Cartridges/MegaBoy.hpp"
+#include "Cartridges/MNetwork.hpp"
+#include "Cartridges/ParkerBros.hpp"
+#include "Cartridges/Pitfall2.hpp"
+#include "Cartridges/Tigervision.hpp"
+#include "Cartridges/Unpaged.hpp"
 
 using namespace Atari2600;
 namespace {
@@ -83,35 +83,35 @@ void Machine::set_switch_is_enabled(Atari2600Switch input, bool state) {
 void Machine::configure_as_target(const StaticAnalyser::Target &target) {
 	const std::vector<uint8_t> &rom = target.cartridges.front()->get_segments().front().data;
 	switch(target.atari.paging_model) {
-		case StaticAnalyser::Atari2600PagingModel::ActivisionStack:	bus_.reset(new Cartridge::CartridgeActivisionStack(rom));	break;
-		case StaticAnalyser::Atari2600PagingModel::CBSRamPlus:		bus_.reset(new Cartridge::CartridgeCBSRAMPlus(rom));		break;
-		case StaticAnalyser::Atari2600PagingModel::CommaVid:		bus_.reset(new Cartridge::CartridgeCommaVid(rom));			break;
-		case StaticAnalyser::Atari2600PagingModel::MegaBoy:			bus_.reset(new Cartridge::CartridgeMegaBoy(rom));			break;
-		case StaticAnalyser::Atari2600PagingModel::MNetwork:		bus_.reset(new Cartridge::CartridgeMNetwork(rom));			break;
-		case StaticAnalyser::Atari2600PagingModel::None:			bus_.reset(new Cartridge::CartridgeUnpaged(rom));			break;
-		case StaticAnalyser::Atari2600PagingModel::ParkerBros:		bus_.reset(new Cartridge::CartridgeParkerBros(rom));		break;
-		case StaticAnalyser::Atari2600PagingModel::Pitfall2:		bus_.reset(new Cartridge::CartridgePitfall2(rom));			break;
-		case StaticAnalyser::Atari2600PagingModel::Tigervision:		bus_.reset(new Cartridge::CartridgeTigervision(rom));		break;
+		case StaticAnalyser::Atari2600PagingModel::ActivisionStack:	bus_.reset(new Cartridge::Cartridge<Cartridge::ActivisionStack>(rom));	break;
+		case StaticAnalyser::Atari2600PagingModel::CBSRamPlus:		bus_.reset(new Cartridge::Cartridge<Cartridge::CBSRAMPlus>(rom));		break;
+		case StaticAnalyser::Atari2600PagingModel::CommaVid:		bus_.reset(new Cartridge::Cartridge<Cartridge::CommaVid>(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::MegaBoy:			bus_.reset(new Cartridge::Cartridge<Cartridge::MegaBoy>(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::MNetwork:		bus_.reset(new Cartridge::Cartridge<Cartridge::MNetwork>(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::None:			bus_.reset(new Cartridge::Cartridge<Cartridge::Unpaged>(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::ParkerBros:		bus_.reset(new Cartridge::Cartridge<Cartridge::ParkerBros>(rom));		break;
+		case StaticAnalyser::Atari2600PagingModel::Pitfall2:		bus_.reset(new Cartridge::Cartridge<Cartridge::Pitfall2>(rom));			break;
+		case StaticAnalyser::Atari2600PagingModel::Tigervision:		bus_.reset(new Cartridge::Cartridge<Cartridge::Tigervision>(rom));		break;
 
 		case StaticAnalyser::Atari2600PagingModel::Atari8k:
 			if(target.atari.uses_superchip) {
-				bus_.reset(new Cartridge::CartridgeAtari8kSuperChip(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari8kSuperChip>(rom));
 			} else {
-				bus_.reset(new Cartridge::CartridgeAtari8k(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari8k>(rom));
 			}
 		break;
 		case StaticAnalyser::Atari2600PagingModel::Atari16k:
 			if(target.atari.uses_superchip) {
-				bus_.reset(new Cartridge::CartridgeAtari16kSuperChip(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari16kSuperChip>(rom));
 			} else {
-				bus_.reset(new Cartridge::CartridgeAtari16k(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari16k>(rom));
 			}
 		break;
 		case StaticAnalyser::Atari2600PagingModel::Atari32k:
 			if(target.atari.uses_superchip) {
-				bus_.reset(new Cartridge::CartridgeAtari32kSuperChip(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari32kSuperChip>(rom));
 			} else {
-				bus_.reset(new Cartridge::CartridgeAtari32k(rom));
+				bus_.reset(new Cartridge::Cartridge<Cartridge::Atari32k>(rom));
 			}
 		break;
 	}
diff --git a/Machines/Atari2600/Cartridges/CartridgeActivisionStack.hpp b/Machines/Atari2600/Cartridges/ActivisionStack.hpp
similarity index 73%
rename from Machines/Atari2600/Cartridges/CartridgeActivisionStack.hpp
rename to Machines/Atari2600/Cartridges/ActivisionStack.hpp
index b79807470..4083bd15c 100644
--- a/Machines/Atari2600/Cartridges/CartridgeActivisionStack.hpp
+++ b/Machines/Atari2600/Cartridges/ActivisionStack.hpp
@@ -6,19 +6,18 @@
 //  Copyright © 2017 Thomas Harte. All rights reserved.
 //
 
-#ifndef Atari2600_CartridgeActivisionStack_hpp
-#define Atari2600_CartridgeActivisionStack_hpp
+#ifndef Atari2600_ActivisionStack_hpp
+#define Atari2600_ActivisionStack_hpp
 
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeActivisionStack: public Cartridge<CartridgeActivisionStack> {
+class ActivisionStack: public BusExtender {
 	public:
-		CartridgeActivisionStack(const std::vector<uint8_t> &rom) :
-			Cartridge(rom),
-			last_opcode_(0x00) {
-			rom_ptr_ = rom_.data();
-		}
+		ActivisionStack(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size),
+			rom_ptr_(rom_base),
+			last_opcode_(0x00) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			if(!(address & 0x1000)) return;
@@ -28,9 +27,9 @@ class CartridgeActivisionStack: public Cartridge<CartridgeActivisionStack> {
 			// RST or JSR.
 			if(operation == CPU::MOS6502::BusOperation::ReadOpcode && (last_opcode_ == 0x20 || last_opcode_ == 0x60)) {
 				if(address & 0x2000) {
-					rom_ptr_ = rom_.data();
+					rom_ptr_ = rom_base_;
 				} else {
-					rom_ptr_ = rom_.data() + 4096;
+					rom_ptr_ = rom_base_ + 4096;
 				}
 			}
 
diff --git a/Machines/Atari2600/Cartridges/CartridgeAtari16k.hpp b/Machines/Atari2600/Cartridges/Atari16k.hpp
similarity index 66%
rename from Machines/Atari2600/Cartridges/CartridgeAtari16k.hpp
rename to Machines/Atari2600/Cartridges/Atari16k.hpp
index c109d76e4..c6559426c 100644
--- a/Machines/Atari2600/Cartridges/CartridgeAtari16k.hpp
+++ b/Machines/Atari2600/Cartridges/Atari16k.hpp
@@ -14,18 +14,17 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeAtari16k: public Cartridge<CartridgeAtari16k> {
+class Atari16k: public BusExtender {
 	public:
-		CartridgeAtari16k(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari16k(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size),
+			rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address >= 0x1ff6 && address <= 0x1ff9) rom_ptr_ = rom_.data() + (address - 0x1ff6) * 4096;
+			if(address >= 0x1ff6 && address <= 0x1ff9) rom_ptr_ = rom_base_ + (address - 0x1ff6) * 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
@@ -36,18 +35,17 @@ class CartridgeAtari16k: public Cartridge<CartridgeAtari16k> {
 		uint8_t *rom_ptr_;
 };
 
-class CartridgeAtari16kSuperChip: public Cartridge<CartridgeAtari16kSuperChip> {
+class Atari16kSuperChip: public BusExtender {
 	public:
-		CartridgeAtari16kSuperChip(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari16kSuperChip(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size),
+			rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address >= 0x1ff6 && address <= 0x1ff9) rom_ptr_ = rom_.data() + (address - 0x1ff6) * 4096;
+			if(address >= 0x1ff6 && address <= 0x1ff9) rom_ptr_ = rom_base_ + (address - 0x1ff6) * 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
diff --git a/Machines/Atari2600/Cartridges/CartridgeAtari32k.hpp b/Machines/Atari2600/Cartridges/Atari32k.hpp
similarity index 66%
rename from Machines/Atari2600/Cartridges/CartridgeAtari32k.hpp
rename to Machines/Atari2600/Cartridges/Atari32k.hpp
index 3ae85f052..facc56e70 100644
--- a/Machines/Atari2600/Cartridges/CartridgeAtari32k.hpp
+++ b/Machines/Atari2600/Cartridges/Atari32k.hpp
@@ -14,18 +14,15 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeAtari32k: public Cartridge<CartridgeAtari32k> {
+class Atari32k: public BusExtender {
 	public:
-		CartridgeAtari32k(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari32k(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size), rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address >= 0x1ff4 && address <= 0x1ffb) rom_ptr_ = rom_.data() + (address - 0x1ff4) * 4096;
+			if(address >= 0x1ff4 && address <= 0x1ffb) rom_ptr_ = rom_base_ + (address - 0x1ff4) * 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
@@ -36,18 +33,15 @@ class CartridgeAtari32k: public Cartridge<CartridgeAtari32k> {
 		uint8_t *rom_ptr_;
 };
 
-class CartridgeAtari32kSuperChip: public Cartridge<CartridgeAtari32kSuperChip> {
+class Atari32kSuperChip: public BusExtender {
 	public:
-		CartridgeAtari32kSuperChip(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari32kSuperChip(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size), rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address >= 0x1ff4 && address <= 0x1ffb) rom_ptr_ = rom_.data() + (address - 0x1ff4) * 4096;
+			if(address >= 0x1ff4 && address <= 0x1ffb) rom_ptr_ = rom_base_ + (address - 0x1ff4) * 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
diff --git a/Machines/Atari2600/Cartridges/CartridgeAtari8k.hpp b/Machines/Atari2600/Cartridges/Atari8k.hpp
similarity index 65%
rename from Machines/Atari2600/Cartridges/CartridgeAtari8k.hpp
rename to Machines/Atari2600/Cartridges/Atari8k.hpp
index 04e489c91..ffaa79433 100644
--- a/Machines/Atari2600/Cartridges/CartridgeAtari8k.hpp
+++ b/Machines/Atari2600/Cartridges/Atari8k.hpp
@@ -14,19 +14,16 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeAtari8k: public Cartridge<CartridgeAtari8k> {
+class Atari8k: public BusExtender {
 	public:
-		CartridgeAtari8k(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari8k(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size), rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address == 0x1ff8) rom_ptr_ = rom_.data();
-			else if(address == 0x1ff9) rom_ptr_ = rom_.data() + 4096;
+			if(address == 0x1ff8) rom_ptr_ = rom_base_;
+			else if(address == 0x1ff9) rom_ptr_ = rom_base_ + 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
@@ -37,19 +34,16 @@ class CartridgeAtari8k: public Cartridge<CartridgeAtari8k> {
 		uint8_t *rom_ptr_;
 };
 
-class CartridgeAtari8kSuperChip: public Cartridge<CartridgeAtari8kSuperChip> {
+class Atari8kSuperChip: public BusExtender {
 	public:
-		CartridgeAtari8kSuperChip(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		Atari8kSuperChip(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size), rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address == 0x1ff8) rom_ptr_ = rom_.data();
-			if(address == 0x1ff9) rom_ptr_ = rom_.data() + 4096;
+			if(address == 0x1ff8) rom_ptr_ = rom_base_;
+			if(address == 0x1ff9) rom_ptr_ = rom_base_ + 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
diff --git a/Machines/Atari2600/Cartridges/CartridgeCBSRAMPlus.hpp b/Machines/Atari2600/Cartridges/CBSRAMPlus.hpp
similarity index 75%
rename from Machines/Atari2600/Cartridges/CartridgeCBSRAMPlus.hpp
rename to Machines/Atari2600/Cartridges/CBSRAMPlus.hpp
index ffde1af7b..1ea652a1b 100644
--- a/Machines/Atari2600/Cartridges/CartridgeCBSRAMPlus.hpp
+++ b/Machines/Atari2600/Cartridges/CBSRAMPlus.hpp
@@ -14,18 +14,15 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeCBSRAMPlus: public Cartridge<CartridgeCBSRAMPlus> {
+class CBSRAMPlus: public BusExtender {
 	public:
-		CartridgeCBSRAMPlus(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_ = rom_.data();
-		}
+		CBSRAMPlus(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size), rom_ptr_(rom_base) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			address &= 0x1fff;
 			if(!(address & 0x1000)) return;
 
-			if(address >= 0x1ff8 && address <= 0x1ffa) rom_ptr_ = rom_.data() + (address - 0x1ff8) * 4096;
+			if(address >= 0x1ff8 && address <= 0x1ffa) rom_ptr_ = rom_base_ + (address - 0x1ff8) * 4096;
 
 			if(isReadOperation(operation)) {
 				*value = rom_ptr_[address & 4095];
diff --git a/Machines/Atari2600/Cartridges/Cartridge.hpp b/Machines/Atari2600/Cartridges/Cartridge.hpp
index 059ae3915..8d49f9f58 100644
--- a/Machines/Atari2600/Cartridges/Cartridge.hpp
+++ b/Machines/Atari2600/Cartridges/Cartridge.hpp
@@ -15,6 +15,17 @@
 namespace Atari2600 {
 namespace Cartridge {
 
+class BusExtender: public CPU::MOS6502::BusHandler {
+	public:
+		BusExtender(uint8_t *rom_base, size_t rom_size) : rom_base_(rom_base), rom_size_(rom_size) {}
+
+		void advance_cycles(int cycles) {}
+
+	protected:
+		uint8_t *rom_base_;
+		size_t rom_size_;
+};
+
 template<class T> class Cartridge:
 	public CPU::MOS6502::BusHandler,
 	public Bus {
@@ -22,11 +33,14 @@ template<class T> class Cartridge:
 	public:
 		Cartridge(const std::vector<uint8_t> &rom) :
 			m6502_(*this),
-			rom_(rom) {}
+			rom_(rom),
+			bus_extender_(rom_.data(), rom.size()) {
+			// The above works because bus_extender_ is declared after rom_ in the instance storage list;
+			// consider doing something less fragile.
+		}
 
-		void run_for(const Cycles cycles) { m6502_.run_for(cycles); }
-		void set_reset_line(bool state) { m6502_.set_reset_line(state); }
-		void advance_cycles(int cycles) {}
+		void run_for(const Cycles cycles)	{ m6502_.run_for(cycles);		}
+		void set_reset_line(bool state)		{ m6502_.set_reset_line(state);	}
 
 		// to satisfy CPU::MOS6502::Processor
 		Cycles perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
@@ -43,11 +57,11 @@ template<class T> class Cartridge:
 			cycles_since_speaker_update_ += Cycles(cycles_run_for);
 			cycles_since_video_update_ += Cycles(cycles_run_for);
 			cycles_since_6532_update_ += Cycles(cycles_run_for / 3);
-			static_cast<T *>(this)->advance_cycles(cycles_run_for / 3);
+			bus_extender_.advance_cycles(cycles_run_for / 3);
 
 			if(operation != CPU::MOS6502::BusOperation::Ready) {
 				// give the cartridge a chance to respond to the bus access
-				static_cast<T *>(this)->perform_bus_operation(operation, address, value);
+				bus_extender_.perform_bus_operation(operation, address, value);
 
 				// check for a RIOT RAM access
 				if((address&0x1280) == 0x80) {
@@ -172,6 +186,9 @@ template<class T> class Cartridge:
 	protected:
 		CPU::MOS6502::Processor<Cartridge<T>> m6502_;
 		std::vector<uint8_t> rom_;
+
+	private:
+		BusExtender bus_extender_;
 };
 
 }
diff --git a/Machines/Atari2600/Cartridges/CartridgeCommaVid.hpp b/Machines/Atari2600/Cartridges/CommaVid.hpp
similarity index 78%
rename from Machines/Atari2600/Cartridges/CartridgeCommaVid.hpp
rename to Machines/Atari2600/Cartridges/CommaVid.hpp
index 26c8e89ce..9a389b43f 100644
--- a/Machines/Atari2600/Cartridges/CartridgeCommaVid.hpp
+++ b/Machines/Atari2600/Cartridges/CommaVid.hpp
@@ -12,11 +12,8 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeCommaVid: public Cartridge<CartridgeCommaVid> {
+class CommaVid: public BusExtender {
 	public:
-		CartridgeCommaVid(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {}
-
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			if(!(address & 0x1000)) return;
 			address &= 0x1fff;
@@ -31,7 +28,7 @@ class CartridgeCommaVid: public Cartridge<CartridgeCommaVid> {
 				return;
 			}
 
-			if(isReadOperation(operation)) *value = rom_[address & 2047];
+			if(isReadOperation(operation)) *value = rom_base_[address & 2047];
 		}
 
 	private:
diff --git a/Machines/Atari2600/Cartridges/CartridgeMNetwork.hpp b/Machines/Atari2600/Cartridges/MNetwork.hpp
similarity index 86%
rename from Machines/Atari2600/Cartridges/CartridgeMNetwork.hpp
rename to Machines/Atari2600/Cartridges/MNetwork.hpp
index b759e70db..187787389 100644
--- a/Machines/Atari2600/Cartridges/CartridgeMNetwork.hpp
+++ b/Machines/Atari2600/Cartridges/MNetwork.hpp
@@ -14,11 +14,11 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeMNetwork: public Cartridge<CartridgeMNetwork> {
+class MNetwork: public BusExtender {
 	public:
-		CartridgeMNetwork(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_[0] = rom_.data() + rom_.size() - 4096;
+		MNetwork(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size) {
+			rom_ptr_[0] = rom_base + rom_size_ - 4096;
 			rom_ptr_[1] = rom_ptr_[0] + 2048;
 			high_ram_ptr_ = high_ram_;
 		}
@@ -28,7 +28,7 @@ class CartridgeMNetwork: public Cartridge<CartridgeMNetwork> {
 			if(!(address & 0x1000)) return;
 
 			if(address >= 0x1fe0 && address <= 0x1fe6) {
-				rom_ptr_[0] = rom_.data() + (address - 0x1fe0) * 2048;
+				rom_ptr_[0] = rom_base_ + (address - 0x1fe0) * 2048;
 			} else if(address == 0x1fe7) {
 				rom_ptr_[0] = nullptr;
 			} else if(address >= 0x1ff8 && address <= 0x1ffb) {
@@ -55,7 +55,6 @@ class CartridgeMNetwork: public Cartridge<CartridgeMNetwork> {
 					}
 				}
 			}
-
 		}
 
 	private:
diff --git a/Machines/Atari2600/Cartridges/CartridgeMegaBoy.hpp b/Machines/Atari2600/Cartridges/MegaBoy.hpp
similarity index 78%
rename from Machines/Atari2600/Cartridges/CartridgeMegaBoy.hpp
rename to Machines/Atari2600/Cartridges/MegaBoy.hpp
index 1d2a09e73..5ef7da21d 100644
--- a/Machines/Atari2600/Cartridges/CartridgeMegaBoy.hpp
+++ b/Machines/Atari2600/Cartridges/MegaBoy.hpp
@@ -14,12 +14,12 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeMegaBoy: public Cartridge<CartridgeMegaBoy> {
+class MegaBoy: public BusExtender {
 	public:
-		CartridgeMegaBoy(const std::vector<uint8_t> &rom) :
-			Cartridge(rom),
+		MegaBoy(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size),
+			rom_ptr_(rom_base),
 			current_page_(0) {
-			rom_ptr_ = rom_.data();
 		}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
@@ -28,7 +28,7 @@ class CartridgeMegaBoy: public Cartridge<CartridgeMegaBoy> {
 
 			if(address == 0x1ff0) {
 				current_page_ = (current_page_ + 1) & 15;
-				rom_ptr_ = rom_.data() + current_page_ * 4096;
+				rom_ptr_ = rom_base_ + current_page_ * 4096;
 			}
 
 			if(isReadOperation(operation)) {
diff --git a/Machines/Atari2600/Cartridges/CartridgeParkerBros.hpp b/Machines/Atari2600/Cartridges/ParkerBros.hpp
similarity index 78%
rename from Machines/Atari2600/Cartridges/CartridgeParkerBros.hpp
rename to Machines/Atari2600/Cartridges/ParkerBros.hpp
index 4138991ba..8a2647460 100644
--- a/Machines/Atari2600/Cartridges/CartridgeParkerBros.hpp
+++ b/Machines/Atari2600/Cartridges/ParkerBros.hpp
@@ -14,11 +14,11 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeParkerBros: public Cartridge<CartridgeParkerBros> {
+class ParkerBros: public BusExtender {
 	public:
-		CartridgeParkerBros(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_[0] = rom_.data() + 4096;
+		ParkerBros(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size) {
+			rom_ptr_[0] = rom_base + 4096;
 			rom_ptr_[1] = rom_ptr_[0] + 1024;
 			rom_ptr_[2] = rom_ptr_[1] + 1024;
 			rom_ptr_[3] = rom_ptr_[2] + 1024;
@@ -30,7 +30,7 @@ class CartridgeParkerBros: public Cartridge<CartridgeParkerBros> {
 
 			if(address >= 0x1fe0 && address < 0x1ff8) {
 				int slot = (address >> 3)&3;
-				rom_ptr_[slot] = rom_.data() + ((address & 7) * 1024);
+				rom_ptr_[slot] = rom_base_ + ((address & 7) * 1024);
 			}
 
 			if(isReadOperation(operation)) {
diff --git a/Machines/Atari2600/Cartridges/CartridgePitfall2.hpp b/Machines/Atari2600/Cartridges/Pitfall2.hpp
similarity index 89%
rename from Machines/Atari2600/Cartridges/CartridgePitfall2.hpp
rename to Machines/Atari2600/Cartridges/Pitfall2.hpp
index c77239113..f383a453f 100644
--- a/Machines/Atari2600/Cartridges/CartridgePitfall2.hpp
+++ b/Machines/Atari2600/Cartridges/Pitfall2.hpp
@@ -12,16 +12,15 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgePitfall2: public Cartridge<CartridgePitfall2> {
+class Pitfall2: public BusExtender {
 	public:
-		CartridgePitfall2(const std::vector<uint8_t> &rom) :
-			Cartridge(rom),
+		Pitfall2(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size),
+			rom_ptr_(rom_base),
 			random_number_generator_(0),
 			featcher_address_{0, 0, 0, 0, 0, 0, 0, 0},
 			mask_{0, 0, 0, 0, 0, 0, 0, 0},
-			cycles_since_audio_update_(0) {
-			rom_ptr_ = rom_.data();
-		}
+			cycles_since_audio_update_(0) {}
 
 		void advance_cycles(int cycles) {
 			cycles_since_audio_update_ += cycles;
@@ -54,11 +53,11 @@ class CartridgePitfall2: public Cartridge<CartridgePitfall2> {
 				break;
 
 				case 0x1008: case 0x1009: case 0x100a: case 0x100b: case 0x100c: case 0x100d: case 0x100e: case 0x100f:
-					*value = rom_[8192 + address_for_counter(address & 7)];
+					*value = rom_base_[8192 + address_for_counter(address & 7)];
 				break;
 
 				case 0x1010: case 0x1011: case 0x1012: case 0x1013: case 0x1014: case 0x1015: case 0x1016: case 0x1017:
-					*value = rom_[8192 + address_for_counter(address & 7)] & mask_[address & 7];
+					*value = rom_base_[8192 + address_for_counter(address & 7)] & mask_[address & 7];
 				break;
 
 #pragma mark - Writes
@@ -82,8 +81,8 @@ class CartridgePitfall2: public Cartridge<CartridgePitfall2> {
 
 #pragma mark - Paging
 
-				case 0x1ff8: rom_ptr_ = rom_.data();		break;
-				case 0x1ff9: rom_ptr_ = rom_.data() + 4096;	break;
+				case 0x1ff8: rom_ptr_ = rom_base_;			break;
+				case 0x1ff9: rom_ptr_ = rom_base_ + 4096;	break;
 
 #pragma mark - Business as usual
 
diff --git a/Machines/Atari2600/Cartridges/CartridgeTigervision.hpp b/Machines/Atari2600/Cartridges/Tigervision.hpp
similarity index 71%
rename from Machines/Atari2600/Cartridges/CartridgeTigervision.hpp
rename to Machines/Atari2600/Cartridges/Tigervision.hpp
index 1abcedac5..4c8e8959f 100644
--- a/Machines/Atari2600/Cartridges/CartridgeTigervision.hpp
+++ b/Machines/Atari2600/Cartridges/Tigervision.hpp
@@ -14,18 +14,18 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeTigervision: public Cartridge<CartridgeTigervision> {
+class Tigervision: public BusExtender {
 	public:
-		CartridgeTigervision(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {
-			rom_ptr_[0] = rom_.data() + rom_.size() - 4096;
+		Tigervision(uint8_t *rom_base, size_t rom_size) :
+			BusExtender(rom_base, rom_size) {
+			rom_ptr_[0] = rom_base + rom_size - 4096;
 			rom_ptr_[1] = rom_ptr_[0] + 2048;
 		}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			if((address&0x1fff) == 0x3f) {
-				int offset = ((*value) * 2048) & (rom_.size() - 1);
-				rom_ptr_[0] = rom_.data() + offset;
+				int offset = ((*value) * 2048) & (rom_size_ - 1);
+				rom_ptr_[0] = rom_base_ + offset;
 				return;
 			} else if((address&0x1000) && isReadOperation(operation)) {
 				*value = rom_ptr_[(address >> 11)&1][address & 2047];
diff --git a/Machines/Atari2600/Cartridges/CartridgeUnpaged.hpp b/Machines/Atari2600/Cartridges/Unpaged.hpp
similarity index 74%
rename from Machines/Atari2600/Cartridges/CartridgeUnpaged.hpp
rename to Machines/Atari2600/Cartridges/Unpaged.hpp
index cc09b5a53..8761d72f5 100644
--- a/Machines/Atari2600/Cartridges/CartridgeUnpaged.hpp
+++ b/Machines/Atari2600/Cartridges/Unpaged.hpp
@@ -14,14 +14,13 @@
 namespace Atari2600 {
 namespace Cartridge {
 
-class CartridgeUnpaged: public Cartridge<CartridgeUnpaged> {
+class Unpaged: public BusExtender {
 	public:
-		CartridgeUnpaged(const std::vector<uint8_t> &rom) :
-			Cartridge(rom) {}
+		Unpaged(uint8_t *rom_base, size_t rom_size) : BusExtender(rom_base, rom_size) {}
 
 		void perform_bus_operation(CPU::MOS6502::BusOperation operation, uint16_t address, uint8_t *value) {
 			if(isReadOperation(operation) && (address & 0x1000)) {
-				*value = rom_[address & (rom_.size() - 1)];
+				*value = rom_base_[address] & (rom_size_ - 1);
 			}
 		}
 };
diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj
index 10b16ea4c..ac8083b5e 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj	
@@ -1036,19 +1036,19 @@
 		4BEA52651DF3472B007E74F2 /* Speaker.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Speaker.hpp; sourceTree = "<group>"; };
 		4BEA52671DF34909007E74F2 /* PIA.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = PIA.hpp; sourceTree = "<group>"; };
 		4BEAC0811E7E0DF800EE56B2 /* Cartridge.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Cartridge.hpp; sourceTree = "<group>"; };
-		4BEAC0821E7E0DF800EE56B2 /* CartridgeActivisionStack.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeActivisionStack.hpp; sourceTree = "<group>"; };
-		4BEAC0831E7E0DF800EE56B2 /* CartridgeAtari16k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeAtari16k.hpp; sourceTree = "<group>"; };
-		4BEAC0841E7E0DF800EE56B2 /* CartridgeAtari32k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeAtari32k.hpp; sourceTree = "<group>"; };
-		4BEAC0851E7E0DF800EE56B2 /* CartridgeAtari8k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeAtari8k.hpp; sourceTree = "<group>"; };
-		4BEAC0861E7E0DF800EE56B2 /* CartridgeCBSRAMPlus.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeCBSRAMPlus.hpp; sourceTree = "<group>"; };
-		4BEAC0871E7E0DF800EE56B2 /* CartridgeCommaVid.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeCommaVid.hpp; sourceTree = "<group>"; };
-		4BEAC0881E7E0DF800EE56B2 /* CartridgeMegaBoy.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeMegaBoy.hpp; sourceTree = "<group>"; };
-		4BEAC0891E7E0DF800EE56B2 /* CartridgeMNetwork.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeMNetwork.hpp; sourceTree = "<group>"; };
-		4BEAC08A1E7E0DF800EE56B2 /* CartridgeParkerBros.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeParkerBros.hpp; sourceTree = "<group>"; };
-		4BEAC08B1E7E0DF800EE56B2 /* CartridgeTigervision.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeTigervision.hpp; sourceTree = "<group>"; };
-		4BEAC08C1E7E0DF800EE56B2 /* CartridgeUnpaged.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CartridgeUnpaged.hpp; sourceTree = "<group>"; };
+		4BEAC0821E7E0DF800EE56B2 /* ActivisionStack.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = ActivisionStack.hpp; sourceTree = "<group>"; };
+		4BEAC0831E7E0DF800EE56B2 /* Atari16k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Atari16k.hpp; sourceTree = "<group>"; };
+		4BEAC0841E7E0DF800EE56B2 /* Atari32k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Atari32k.hpp; sourceTree = "<group>"; };
+		4BEAC0851E7E0DF800EE56B2 /* Atari8k.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Atari8k.hpp; sourceTree = "<group>"; };
+		4BEAC0861E7E0DF800EE56B2 /* CBSRAMPlus.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CBSRAMPlus.hpp; sourceTree = "<group>"; };
+		4BEAC0871E7E0DF800EE56B2 /* CommaVid.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = CommaVid.hpp; sourceTree = "<group>"; };
+		4BEAC0881E7E0DF800EE56B2 /* MegaBoy.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = MegaBoy.hpp; sourceTree = "<group>"; };
+		4BEAC0891E7E0DF800EE56B2 /* MNetwork.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = MNetwork.hpp; sourceTree = "<group>"; };
+		4BEAC08A1E7E0DF800EE56B2 /* ParkerBros.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = ParkerBros.hpp; sourceTree = "<group>"; };
+		4BEAC08B1E7E0DF800EE56B2 /* Tigervision.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Tigervision.hpp; sourceTree = "<group>"; };
+		4BEAC08C1E7E0DF800EE56B2 /* Unpaged.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Unpaged.hpp; sourceTree = "<group>"; };
 		4BEAC08D1E7E0E1A00EE56B2 /* Bus.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Bus.hpp; sourceTree = "<group>"; };
-		4BEAC08E1E7E110500EE56B2 /* CartridgePitfall2.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CartridgePitfall2.hpp; sourceTree = "<group>"; };
+		4BEAC08E1E7E110500EE56B2 /* Pitfall2.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Pitfall2.hpp; sourceTree = "<group>"; };
 		4BEE0A6A1D72496600532C7B /* Cartridge.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = Cartridge.cpp; sourceTree = "<group>"; };
 		4BEE0A6B1D72496600532C7B /* Cartridge.hpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.h; path = Cartridge.hpp; sourceTree = "<group>"; };
 		4BEE0A6D1D72496600532C7B /* PRG.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = PRG.cpp; sourceTree = "<group>"; };
@@ -2216,18 +2216,18 @@
 			isa = PBXGroup;
 			children = (
 				4BEAC0811E7E0DF800EE56B2 /* Cartridge.hpp */,
-				4BEAC0821E7E0DF800EE56B2 /* CartridgeActivisionStack.hpp */,
-				4BEAC0831E7E0DF800EE56B2 /* CartridgeAtari16k.hpp */,
-				4BEAC0841E7E0DF800EE56B2 /* CartridgeAtari32k.hpp */,
-				4BEAC0851E7E0DF800EE56B2 /* CartridgeAtari8k.hpp */,
-				4BEAC0861E7E0DF800EE56B2 /* CartridgeCBSRAMPlus.hpp */,
-				4BEAC0871E7E0DF800EE56B2 /* CartridgeCommaVid.hpp */,
-				4BEAC0881E7E0DF800EE56B2 /* CartridgeMegaBoy.hpp */,
-				4BEAC0891E7E0DF800EE56B2 /* CartridgeMNetwork.hpp */,
-				4BEAC08A1E7E0DF800EE56B2 /* CartridgeParkerBros.hpp */,
-				4BEAC08B1E7E0DF800EE56B2 /* CartridgeTigervision.hpp */,
-				4BEAC08C1E7E0DF800EE56B2 /* CartridgeUnpaged.hpp */,
-				4BEAC08E1E7E110500EE56B2 /* CartridgePitfall2.hpp */,
+				4BEAC0821E7E0DF800EE56B2 /* ActivisionStack.hpp */,
+				4BEAC0851E7E0DF800EE56B2 /* Atari8k.hpp */,
+				4BEAC0831E7E0DF800EE56B2 /* Atari16k.hpp */,
+				4BEAC0841E7E0DF800EE56B2 /* Atari32k.hpp */,
+				4BEAC0861E7E0DF800EE56B2 /* CBSRAMPlus.hpp */,
+				4BEAC0871E7E0DF800EE56B2 /* CommaVid.hpp */,
+				4BEAC0881E7E0DF800EE56B2 /* MegaBoy.hpp */,
+				4BEAC0891E7E0DF800EE56B2 /* MNetwork.hpp */,
+				4BEAC08A1E7E0DF800EE56B2 /* ParkerBros.hpp */,
+				4BEAC08E1E7E110500EE56B2 /* Pitfall2.hpp */,
+				4BEAC08B1E7E0DF800EE56B2 /* Tigervision.hpp */,
+				4BEAC08C1E7E0DF800EE56B2 /* Unpaged.hpp */,
 			);
 			path = Cartridges;
 			sourceTree = "<group>";